Replaceable earthworking tips or teeth commonly used on rippers, loader buckets and trenchers must be positively secured in place on their support adapters and yet be capable of quick removal for replacement purposes. In addition to the monetary value of the tip that is lost, the loss of the tip will subject the adapter to damage requiring time consuming expensive repairs and/or replacement. Loss of the tip, when used in conjunction with rock crushing equipment, causes severe damage to the equipment should it become digested or jammed therein.
Prior art retaining pins for securing an earthworking tip on its adapter have not been totally successful especially when used in combination with impact rippers. In such application, the retaining pins are subjected to extreme vibration resulting in breakage of the pins or the retaining mechanism becoming loose causing loss of the pin and the tip.
Typically, retaining devices have been employed which relies on friction between mating surfaces for retention, U.S. Pat. No. 3,624,827 issued to Richard K. Liess et al. on Nov. 30, 1971, discloses a retaining pin having a friction ring disposed in a deep, wide, central groove of the pin. The pin is retained in a bore defined by the adapter nose solely by friction between the ring and the bore. Although this type of pin has been successful in normal ripper and bucket tip retaining applications, the central groove materially reduces the strength of the pin and subjects it to early failure in extremely severe applications. In addition, the pin can vibrate out of the bore since it is not positively retained.
U.S. Pat. No. 3,959,901 issued to Gene R. Klett on June 1, 1976, discloses another friction type retaining device in which the pin is retained solely by frictional engagement of the retaining pin with a lock ring. As before, vibration allows the pin to work its way loose resulting in loss of the pin and the separation of the tip from the adapter.
U.S. Pat. No. 3,952,433 issued to Lloyd K. Heinold et al. on Apr. 27, 1976, and U.S. Pat. No. 3,990,162 issued to Lloyd K. Heinold et al. on Nov. 9, 1976, disclose spring clips that straddle diametrially opposite sides of the retaining pin in expanded friction engagement. The clips are substantially encapsulated by an elastomeric material which aids in maintaining the spring clips in frictional engagement with the pins. Undesirably, the spring clips only partially engage the pins and the pins are easily removed by the spreading of the spring clips.
Accordingly, an improved earthworking device is provided so constructed that the earthworking tip is retained on the nose of the adapter by a pin that is positively retained in aligned apertures in the earthworking tip and the bore of the adapter. Preferably, the retaining pin is positively secured by a keeper means that is simple and economical in construction while maintaining the pin against outward axial movement during operation of the earthworking device.
The present invention is directed to overcoming one or more of the problems as set forth above.